Apparatus and knife for the production of wood chips from logs



H. W. WEXELL APPARATUS AND KNIFE FOR THE PRODUCTION Oct. 17, 19673,347,291

OF WOOD'CHIPS FROM LOGS Flled Jan 14 1965 4 Sheets-Sheet 1 INVENTOR h.14/. Vl/EXEL'L '1 w awrJw- ATTORNEYS Oct. 17, 1967 Filed Jan. 14, 1965H. W. WEXELL APPARATUS AND KNIFE FOR THE PRODUCTION OF WOOD CHIPS FROMLOGS 4 Sheets-Sheet 2 INVENTOR H. W Wa /v54 4 ATTORNEYS Oct. 17, 1967 H.w. WEXELL 3,347,291

APPARATUS AND KNIFE FOR THE PRODUCTION OF WOOD CHIPS FROM LOGS FiledJan. 14, 1965 4 Sheets-Sheet 3 INVENTOR BY dwam' WM ATTORNEYS Oct. 17,1967 H, w. WEXELL 3,347,291

APPARATUS AND KNIFE FOR THE PRODUCTION OF WOOD. CHIPS FROM LOGS FiledJan. 14, 1965 4 Sheets-Sheet 4 ATTORNEYS United States Patent 3,347,291APPARATUS AND KNIFE FOR THE PRODUC- TION 0F WOOD CHIPS FROM LOGS HarryWilhelm Wexell, Gavle, Sweden, assignor to Brundell & JonssonAktiebolag, Gavle, Sweden Filed Jan. 14, 1965, Ser. No. 425,493 Claims.(Cl. 144-472) This invention relates to woodworking and moreparticularly to an apparatus for the production of wood chips from logsand also to a multiple unit knife having a plurality of longitudinallyspaced cutting components thereon particularly adapted for use in theapparatus and the apparatus of this invention is primarily intended forreducing an entire log to usable chips.

It has been found that the character of chips utilized in the productionof wood pulp has a material bearing on the qualtiy of such pulp,particularly as regards the strength thereof and it has further beenfound that the quality of the pulp is materially improved by utilizingchips in which there is substantially no distortion or displacement ofthe wood fibers, one with respect to the other.

Heretofore in the production of wood chips, the primary considerationhas been the rapid reduction of a log to chip form without anyparticular concern as to the uniformity of the chips produced withrespect to dimensions and also no particular consideration has beengiven to the matter of preventing distortion or displacement of thefibers in the chips.

Admittedly, some attempts have heretofore been made to produce highquality chips having uniform characteristics, such as uniform width andthickness and also having undistorted fibers and such chips have beenproduced, at least on an experimental basis, by utilizing a conventionalveneer lathe to cut sheets from a log with such sheets being thereaftercut into chip form. The chips produced in this manner result inproviding pulp of superior characteristics, but this method ofproduction has no practical utility, since the same is relatively slow,requires both a veneer lathe and apparatus to cut the resulting veneerinto chips and furthermore, after the maximum quantity of veneer hasbeen removed from the log, a core remains which must either be discardedor utilized in some other manner.

A further attempt has been made to solve this problem by the provisionof a so-called drum chipper which takes the form of a relatively largecylindrical drum mounted for rotation on a horizontal shaft and withcutters projecting from the periphery of the drum. The drum is rotatedat a relatively slow speed and logs are forced transversely against theside of the drum which results in the cutting of strips crosswise of thelog by the cutters and such cuts are generally parallel to the directionof the fibers in the log. These strips which have a substantiallyuniform thickness pass through slits into the interior of the drumagainst the action of centrifugal force and are discharged from the drumthrough one or both ends. The resulting chips are only uniform as tothickness, the other dimensions being variable and while such chips aresuperior to the chips previously produced by a conventional chippingapparatus there are serious disadvantages to this type of chippingapparatus, in that for an acceptable production rate the apparatus mustbe relatively large and, therefore, costly and furthermore, the logsutilized therewith must be of substantially uniform, relatively shortlengths and also the power requirements for such an apparatus arerelatively large.

It is accordingly an object of the invention to provide an apparatus forthe production of wood chips from logs, which apparatus operates toprovide a chip of superior characteristics, which chips may be producedat a relatively rapid rate and with minimum power requirement partiallydue to the fact that chips are'discharged outwardly in a radialdirection assisted by centrifugal force.

A further object of the invention is the provision of an apparatus forthe production of chips from logs, which apparatus serves to accommodatelogs of any length and also over a relatively wide range of diameters.

A still further object of the invention is the provision of an apparatusfor reducing an entire log to usable cli'ips of substantially uniformwidth and thickness.

Another object of the invention is the provision of an apparatus forreducing logs to chips, which apparatus includes a rotatable drumdisposed on a horizontal axis with cutters secured to the drum andprojecting inwardly thereof and with logs being fed longitudinally intothe drum.

A further object of the invention is the provision of an apparatus forthe production of chips from logs, such apparatus including a rotatablymounted elongated, hollow frusto-conical drum open at one end, such drumhaving a plurality of circumferentially spaced longitudinally extendingslots therein and with an elongated multiple unit knife secured in eachslot and projecting into the interior of the drum chips being dischargedradially outwardly through the slots, such discharge being assisted bythe action of centrifugal force.

A further object of the invention is the provision of an apparatus forproducing wood chips from logs, such apparatus including a rotatablymounted hollow di-um there being a plurality of circumferentially spacedmultiple unit knives secured to the drum and projecting inwardly thereofwith the cutting components of the knives displaced longitudinally withrespect to each other in order to provide successive overlapping cuttingedges disposed in helical spiral paths longitudinally of the drum.

A still further object of the invention is the provision of an apparatusfor the production of wood chips from logs, such apparatus including arotatably mounted hollow drum there being a plurality ofcircumferentially spaced longitudinally extending slots in the drum,each slot serving to receive a multiple unit knife and there being meansfor removably securing such knives in adjusted position and forpermitting convenient removal or replacement thereof.

Another object of the invention is the provision of a multiple unitknife for use in an apparatus for the production of wood chips fromlogs, such knife including a plurality of cutting components, eachcomponent having a shaving edge joined at one end by an angularlyrelated parting edge with the shaving edges of the components on eachknife being substantially parallel and arranged in echelon with respectto the lines of parallelism of the shaving edges.

A further object of the invention is the provision of a multiple unitknife for use in an apparatus for the production of wood chips fromlogs, such knife including a plurality of cutting components, eachcomponent having a shaving edge joined at one end by an angularlyrelated parting edge and with adjacent cutting components spaced fromeach other with the intervening portion of the knife edge being relievedto provide non-cutting portions between the terminal end of a partingedge of one component and the terminal end of the shaving edge of thenext adjacent component.

A still further object of the invention is the provision of a multipleunit knife for use in an apparatus for the production of wood chips fromlogs, such knife including a plurality of cutting components having ashaving edge joined at one end by an angularly related parting edge, theobverse surface of the knife blade which terminates in the shaving andparting edges being corrugated with the lines of corrugation beingsubstantially parallel and extending generally transversely from thepoint of juncture between the shaving edge and the parting edge of eachcomponent.

A further object of the invention is the provision of a multiple unitknife for use in an apparatus for the production of wood chips fromlogs, such knife including a blade having a plurality of cuttingcomponents, each having a shaving edge joined at one end by an angularlyrelated parting edge and in which the blade is formed of corru gatedmaterial of substantially uniform thickness.

Further objects and advantages of the invention will be apparent fromthe following description taken in conjunction with accompanyingdrawings wherein:

FIG. 1 is a view in perspective showing the drum of an apparatus for theproduction of wood chips from logs, together with the manner in whichthe multiple unit knives are disposed in the drum, as well as the mannerof feeding a log to the drum to be reduced to chips;

FIG. 2 a fragmentary view in perspective showing the manner in which themultiple unit knives are secured in place in circumferentially spacedslots in the drum shown in FIG. 1;

FIG. 3 a top plan view of a multiple unit knife for use in the chippingapparatus of FIG. 1;

FIG. 4 a front elevational view of the multiple unit knife of FIG. 3;

FIG. 5 a bottom plan view of the knife of FIG. 3',

FIG. 6 a sectional view taken substantially on the line 66 of FIG. 3;

FIG. 7 a front elevational view showing a multiple unit knife formed ofcorrugated material of substantially uniform thickness;

FIG. 8 a fragmentary view in perspective similar to FIG. 2, but showingthe manner in which the corrugated knife of FIG. 7 is secured in thedrum;

FIG. 9 a View in perspective showing a wood chip produced by theapparatus and knife of this invention; and

FIG. 10 a transverse sectional view of the chip shown in FIG. 9.

With continued reference to the drawings, there is shown in FIGS. 1 and2 a hollow drum 10 which may be utilized in an apparatus for producingwood chips from logs, the drum 10, as shown in FIGS. 1 and 2, beinghollow and frusto-conical in form by a proper disposition of the cuttersin the drum in a manner to be later described, such drum may, ifdesired, be cylindrical in formation. The drum 10 may be rotatablysupported in any suitable manner by a shaft 11 and, of course, suitablemean for driving the drum will be provided.

The drum 10 may be provided with a plurality of circumferentially spacedlongitudinally extending slots 12 and such slots may be closed at theend of the drum remote from the shaft 11 by a ring 13 which may berernovably secured in place by a screw threaded or other suitablefastening means 14. One side of each slot 12 is beveled to provide aknife blade engaging and supporting surface 15. A plurality of ears 16are provided adjacent the outer edge of the beveled surface 15 and theears 16 are provided with aligned apertures 17 which serve to receive arod 18 on which is pivotally mounted a clamping jaw 19 having a beveledclamping surface 20 and clamping screws 21 may be threadedly received ina segmental cover plate 22 which is secured to the outer surface of thedrum 10 between each adjacent pair of slots 12 and with one edge 23 ofthe cover plate 22 overhanging the adjacent beveled surface 15 and as isclearly shown in FIG. 2, the clamping screws 21 engage the clamping jaw20 and serve to urge the same toward the beveled surface 15. Thesegmental cover plate 22 may be removably secured to the drum 10 byscrew threaded or other suitable fastening means 24. The space betweenthe overhanging edge 23 of the cover plate 22 and clamping jaw 20 may beclosed by an elongated closure plate 25 secured to the clamping jaw 19and overlapping the overhanging edge 23 of the cover plate 22.

A multiple unit knife 26, the structure of which will be laterdescribed, is disposed in each slot 12 with the reverse surface of theknife 26 engaging the beveled surface 15 of the drum 10 and with aclamping bar 27 engaging the upper face of the knife 26 and the clampingjaw 19 is urged into engagement with the clamping bar 27 to securelyclamp the knife 26 in place in engagement with the beveled surface 15.The knife 26 may be released for adjustment or removal by suitablemanipulation of the clamping screws 21.

With particular reference to FIGS. 3 to 6, there is shown therein thestructural details of the multiple unit knife 26 and as clearly shown inthese figures, such knife may comprise an elongated blade carrying aplurality of cutting components, each of which comprises a shaving orslicing edge 28 joined at one end by an angularly related parting edge29. All of the shaving edges 28 are substantially parallel and arearranged in echelon with respect to the lines of parallelism of theshaving edges 28. The cutting components provided by the shaving andparting edges 28 and 29 are longitudinally spaced from each other andthe intervening portion 30 between adjacent cutting components isrelieved to provide a non-cutting portion between the terminal end 31 ofa parting edge 29 and the terminal end 32 of the next adjacent shavingedge 28. The included angle between the shaving edge 28 and the partingedge 29 of each component in the general plane of the blade 28 is obtuseand furthermore, the shaving edge 28 and the parting edge 29 of eachcomponent are angularly related with respect to a plane normal to thegeneral plane of blade 28 and the included angle in this plane is alsoobtuse.

As clearly shown in FIGS. 3 and 4, the obverse surface 33 of the blade28 is corrugated with the lines of corrugation being substantiallyparallel and extending generally transversely from the point of juncturebetween the cutting edges 28 and 29 of each component and the lines ofcorrugation substantially bisect the included angle of each component inthe general plane of the blade. In this form of cutting knife, thereverse face 34 of the blade 28 is plane and the obverse face 33 and thereverse face 34 are joined at the cutting edges by clearance faces 35formed to provide acute included angles between the clearance faces 35and the obverse face 33 of the blade 28.

Again referring to FIG. 2, the surface of the clamping bar 27 engagingthe obverse face 33 of the knife 26 is formed complementary to thecorrugated obverse face 33 in such a manner as to mate therewith andthereby securely hold the knife 26 in place in engagement with thebeveled surface 15 of the drum 10.

With particular reference to FIG. 7, there is shown a somewhat modifiedform of multiple unit knife in which there is provided a blade 36 formedof corrugated material of substantially uniform thickness and such bladeis also formed to provide shaving edges 37 and parting edges 38 whichare formed in the same manner and have the same relationship as thecorresponding edges of the knife shown in FIGS. 3 to 6 and describedabove. The corrugated knife shown in FIG. 7 is secured in the slot 12 ofthe drum 10 in exactly the same manner as described above in connectionwith the knife having a plane reverse face and with particular referenceto FIG. 8, it will be seen that whereas as shown in FIG. 2, the beveledsurface 15 is flat, in FIG. 8 the beveled surface 3 9 is corrugated tocorrespond to the beveled reverse face 40 of the corrugated knife 36,and, therefore, the corrugated beveled surface 39 will mate with thebeveled reverse face of the knife 36 and securely hold the same inposition in the drum 10.

With particular reference to FIG. 1, the interior surface of the drum 10may be provided with spiral grooves 41 which, in effect, formcontinuations of the shearing edges 28 and parting edges 29 of thecutting component of the knife 26 and such grooves 41 provide clearancespaces for these cutting edges on the interior of the drum 10. Theadjacent knives 26 disposed in the grooves 12 of the drum are displacedlongitudinally with respect to each other a distance less than thedistance between adjacent cutting components to provide successiveoverlapping cutting edges disposed in helical spiral pathslongitudinally of the drum 10 and by reason of this disposition of theknives 26 when a log 42 is fed longitudinally into the open end of thedrum 10 in the direction in which the axis of the log 42 issubstantially parallel to the shearing edges 28 of the knives 2-6 uponrotation of the drum 10 a succession of helicoidal chips 43 as shown inFIGS. 9 and 10, will be removed from the log 42 with the chips 43 beingsubstantially in the form of a parallelogram in cross section with thesurface 44 of the chip 43 being removed from the log 42 by the shearingedges 28 in directions substantially parallel to the fibers of the log42 and with the side edges 45 of the chip 43 being severed from the logsby the parting edges 29 substantially across the grain of the log 42,thereby preventing crushing of the fibers in the chips 43 to provide achip of superior quality.

It will be seen that by the above described invention there has beenprovided an apparatus for producing wood chips from logs, whichapparatus is relatively simple in construction and which may beconveniently provided in the form of a portable apparatus for use in thewoods to reduce logs to chip form immediately after felling thereof andfurthermore, by the provision of a multiple unit knife for use in thedrum of the apparatus of this invention, the structure thereof has beenmaterially simplified when compared to prior art apparatus in which aplurality of knives are utilized, each knife providing an individualcutting component. As stated above, the drum 10 as shown in FIG. 1, isfrusto-conical in form, but the same may, if desired, be provided as acylindrical drum in which case the knives 26 are arranged in such amanner as to dispose the shearing edges 28 parallel to the axis of a log42 to be fed thereto and with such shearing edges 28 arranged in echelonin the same manner as described in conjunction with a frusto-conicaldrum. Furthermore, the manner of positioning and securing the knives inthe drum is relatively simple and permits convenient adjustment orreplacement of the knives and the chips removed from the log aredischarged outwardly through the slots 12 in a manner whereby suchdischarge of the chips is assisted by centrifugal force.

It will be obvious to those skilled in the art that various changesmay-be made in the invention without departing from the spirit and scopethereof and therefore the invention is not limited by that which isshown in the drawings and described in the specification, but only asindicated in the appended claims.

What is claimed is:

1. An apparatus for the production of wood chips from logs, saidapparatus comprising an elongated hollow drum open at one end, means formounting said drum for rotation about the longitudinal axis, said drumhaving a plurality of circumferentially spaced longitudinally extendingslots in the peripheral wall, a removable ring secured to' saiddrur'nand closing said slots at the open end of said drum, one side ofeach slot being beveled to provide a knife engaging and supportingsurface, an elongated multiple unit knife having an obverse and areverse face disposed in each slot with said reverse face engaging saidbeveled surface, each knife comprising a blade carrying a plurality oflongitudinally spaced cutting components, each component having ashaving edge joined at one end by an angularly related parting edge, theshaving edges of the components being substantially parallel andarranged in echelon with respect to the lines of parallelism of theshaving edges, said shaving and parting edges projecting inwardly of theinner surface of said drum with the distance from the shaving andparting edges to the longitudinal axis of said drum progressivelydecreasing from the open end of said drum toward the opposite end,adjacent knives .being displaced longitudinally with respect to eachother a distance less than the distance between adjacent cuttingcomponents to provide successive overlapping cutting edges disposed inhelical spiral paths longitudinally of said drum, a clamping barengaging the obverse face of each knife, a clamping jaw pivotallymounted on said drum adjacent each slot, and means for urging each jawinto engagement with each clamping bar to clamp each knife in place inengagement with said beveled surface, whereby upon rotation of said drumand feeding of log longitudinally into the open end of said drum intoengagement with said knives, helical chips of substantially uniformthickness will be removed from the log and discharged outwardly throughsaid slots with said shaving edges cutting substantially parallel to thefibers in said log and said parting edges cutting across the fibers atan angle thereto.

2. An apparatus as defined in claim 1, in which the inner surface ofsaid drum is provided with helical clearance grooves, said grooveshaving substantially the same configuration as the cutting edges of saidknife.

3. An apparatus as defined in claim 1, in which the obverse face of saidknife is corrugated and the reverse face is plane.

4. An apparatus as defined in claim 3 in which the surface of saidclamping bar engaging said knife is formed complementary to the obverseface of said knife to mate therewith and provide clamping engagementover substantially the entire knife contacting area of said bar.

5. An apparatus as defined in claim 1, in which said knife is formed ofcorrugated material of substantially uniform thickness, said beveledsurface being corrugated to mate with the corrugated reverse face ofsaid knife.

6. An apparatus as defined in claim 5, in which the surface of saidclam-ping bar engaging said knife is formed complementary to the obverseface of said knife to mate therewith and provide clamping engagementover substantially the entire knife contacting area of said bar.

7. An apparatus as defined in claim 1, in which a segmental cover plateis secured to said drum between each pair of adjacent slots, one edge ofeach plate overhanging the adjacent beveled surface, the means forurging each jaw into engagement with each clamping bar comprising screwthreaded means threadedly received in each overhanging edge of saidplate and engaging each jaw.

8. An apparatus as defined in claim 7, in which an elongated closureplate is fixed to each jaw and overlaps the overhanging edge of eachcover plate to close the space between each jaw and each cover plate.

9. An apparatus for the production of wood chips from logs, saidapparatus comprising an elongated hollow drum open at one end, means formounting said drum for rotation about the longitudinal axis, said drumhaving a plurality of circumferentially spaced longitudinally extendingslots in the peripheral wall, one side of each slot being beveled toprovide a knife engaging and suporting surface, an elongated multipleunit knife having an observe and a reverse face disposed in each slotwith said reverse face engaging said beveled surface, each knifecomprising a blade carrying a plurality of longitudinally spaced cuttingcomponents, each component having a shaving edge joined at one end by anangularly related parting edge, the shaving edges of the componentsbeing substantially parallel and arranged in echelon with respect to thelines of parallelism of the shaving edges, said shaving and partingedges projecting inwardly of the inner surface of said drum with thedistance from the shaving and parting edges to the longitudinal axis ofsaid drum progressively decreasing from the open end of said drum towardthe opposite end, adjacent knives being displaced longitudinally withrespect to each other a distance less than the distance between adjacentcutting components to provide successive overlapping cutting edgesdisposed in helical spiral paths longitudinally of said drum, a clampingbar engaging the obverse face of each knife, a clamping jaw pivotallymounted on said drum adjacent each slot, and means for urging each jawinto engagement with each clamping bar to clamp each knife in place inengagement with said beveled surface, whereby upon rotation of said drumand feeding of a log longitudinally into the open end of said drum intoengagement wit-h said knives, helical chips of substantially uniformthickness will be removed from the log and discharge outwardly throughsaid slots with said shaving edges cutting substantially parallel to thefibers in said log and said parting edges cutting across the fibers atan angle thereto.

10. An apparatus for the production of wood chips from logs, saidapparatus comprising an elongated hollow drum open at one end, means formounting said drum for rotation about the longitudinal axis, said drumhaving a plurality of circumferentially spaced longitudinally extendingslots in the peripheral wall, one side of each slot being beveled toprovide a knife engaging and supporting surface, an elongated multipleunit knife having an obverse and a reverse face disposed in each slotwith said reverse face engaging said beveled surface, each knifecomprising a blade carrying a plurality of longitudinally spaced cuttingcomponents, each component having a shaving edge joined at one end by anangularly related parting edge, the shaving edges of the componentsbeing substantially parallel and arranged in echelon with respect to thelines of parallelism of the shaving edges, said shaving and partingedges projecting inwardly of the inner surface of said drum with thedistance from the shaving and parting edges to the longitudinal axis ofsaid drum progressively decreasing from the open end of said drum towardthe opposite end, adjacent knives being displaced longitudinally wit-hrespect to each other a distance less than the distance between adjacentcutting components to provide successive overlapping cutting edgesdisposed in helical spiral paths longitudinally of said drum and meansto clamp each knife in place in engagement with said beveled surface,whereby upon rotation of said drum and feeding of a log longitudinallyinto the open end of said drum into engagement with said knives, helicalchips of substantially uniform thickness will be removed from the logand discharged outwardly through the said slots with said shaving edgescutting substantially parallel to the fibers in said log and saidparting edges cutting across the fibers at an angle thereto.

11. An apparatus for the production of wood chips from logs, saidapparatus comprising an elongated hollow drum open at one end, means formounting said drum [for rotation about the longitudinal axis, said drumhaving a plurality of circumferentially spaced longitudinally extendingslots in the peripheral Wall, an elongated multiple unit knife disposedin each slot, each knife comprising a blade carrying a plurality oflongitudinally spaced cutting components, each component having ashaving edge joined at one end by an angularly related parting edge, theshaving edges of the components being substantially parallel andarranged in echelon with respect to the lines of parallelism of theshaving edges, said shaving and parting edges projecting inwardly of theinner surface of said drum with the distance from the shaving andparting edges to the longitudinal axis of said drum 8 progressivelydecreasing from the open end of said drum toward the opopsite end,adjacent knives being displaced longitudinally with respect to eachother a distance less than the distance between adjacent cuttingcomponents to provide successive overlapping cutting edges disposed inhelical spiral paths longitudinally of said drum, and means to clampeach knife in place in each slot, whereby upon rotation of said drum andfeeding of a log longitudinally into the open end of said drum intoengagement with said knives, helical chips of substantially uniformthickness will be removed from the log and discharge outwardly throughsaid slots with said shaving edges cutting substantially parallel to thefibers in said log and said parting edges cutting across the fibers atan angle thereto.

12. A multiple unit knife comprising a blade carrying a plurality ofcutting components longitudinally spaced from each other, each componenthaving a shaving edge joined at one end by an angularly related partingedge, the shaving edges of the components being substantially paralleland arranged in echelon with respect to the lines of parallelism of theshaving edges, and with the intervening portions of the blade edge beingrelieved to provide a noncutting portion between the terminal end of theparting edge of one component and the terminal end of the shaving edgeof the next adjacent component.

13. A knife as defined in claim 12, in which the included angle betweenthe two edges of each component in the general plane of said blade is anobtuse angle.

14. A knife as defined in claim 13, in which the two edges of eachcomponent are angularly related with respect to a plane normal to saidgeneral plane of the blade.

15. A knife as defined in claim 14, in which the included angle betweenthe two edges of each of said components in said plane normal to saidgeneral plane is obtuse.

16. A knife as defined in claim 15, in which the obverse surface of saidblade and which terminates in said edges is corrugated with the lines ofcorrugation being substantially parallel and extending generallytransversely from the point of juncture between the two cutting edges ofeach component.

17. A knife as defined in claim 16, in which said lines of corrugationsubstantially bisect the included angle of each component in saidgeneral plane of the blade.

18. A knife as defined in claim 17, in which said obverse face of theblade and the reverse face thereof are joined by clearance facesdisposed to provide acute included angles between the clearance facesand said obverse face.

19. A knife as defined in clai m18, in which said reverse face of saidblade is plane.

20. A knife as defined in claim 18, in which said blade is formed ofcorrugated material of substantially uniform thickness.

References Cited UNITED STATES PATENTS 3,216,470 11/1965 Nilsson 144-172X FOREIGN PATENTS 868,208 5/ 1961 Great Britain.

WILLIAM W. DYER, 111., Primary Examiner.

W. D. BRAY, Assistant Examiner.

1. AN APPARATUS FOR THE PRODUCTION OF WOOD CHIPS FROM LOGS, SAIDAPPARATUS COMPRISING AN ELONGATED HOLLOW DRUM OPEN AT ONE END, MEANS FORMOUNTING SAID DRUM FOR ROTATION ABOUT THE LONGITUDINAL AXIS, SAID DRUMHAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED LONGITUDINALLY EXTENDINGSLOTS IN THE PERIPHERAL WALL, A REMOVABLE RING SECURED TO SAID DRUM ANDCLOSING SAID SLOTS AT THE OPEN END OF SAID DRUM, ONE SIDE OF EACH SLOTBEING BEVELED TO PROVIDE A KNIFE ENGAGING AND SUPPORTING SURFACE, ANELONGATED MULTIPLE UNIT KNIFE HAVING AN OBVERSE AND A REVERSE FACEDISPOSED IN EACH SLOT WITH SAID REVERSE FACE ENGAGING SAID BEVELEDSURFACE, EACH KNIFE COMPRISING A BLADE CARRYING A PLURALITY OFLONGITUDINALLY SPACED CUTTING COMPONENTS, EACH COMPONENT HAVING ASHAVING EDGE JOINED AT ONE END BY AN ANGULARLY RELATED PARTING EDGE, THESHAVING EDGES OF THE COMPONENTS BEING SUBSTANTIALLY PARALLEL ANDARRANGED IN ECHELON WITH RESPECT TO THE LINES OF PARALLELISM OF THESHAVING EDGES, SAID SHAVING AND PARTING EDGES PROJECTING INWARDLY OF THEINNER SURFACE OF SAID DRUM WITH THE DISTANCE FROM THE SHAVING ANDPARTING EDGES TO THE LONGITUDINAL AXIS OF SAID DRUM PROGRESSIVELYDECREASING FROM THE OPEN END OF SAID DRUM TOWARD THE OPPOSITE END,ADJACENT KNIVES BEING DISPLACED LONGITUDINALLY WITH RESPECT TO EACHOTHER A DISTANCE LESS THAN THE DISTANCE BETWEEN ADJACENT CUTTINGCOMPONENTS TO PROVIDE SUCCESSIVE OVERLAPPING CUTTING EDGES DISPOSED INHELICAL SPIRAL PATHS LONGITUDINALLY OF SAID DRUM, A CLAMPING BARENGAGING THE OBVERSE FACE OF EACH KNIFE, A CLAMPING JAW PIVOTALLYMOUNTED ON SAID DRUM ADJACENT EACH SLOT, AND MEANS FOR URGING EACH JAWINTO ENGAGEMENT WITH EACH CLAMPING BAR TO CLAMP EACH KNIFE IN PLACE INENGAGEMENT WITH SAID BEVELED SURFACE, WHEREBY UPON ROTATION OF SAID DRUMAND FEEDING OF LOG LONGITUDINALLY INTO THE OPEN END OF SAID DRUM INTOENGAGEMENT WITH SAID KNIVES, HELICAL CHIPS OF SUBSTANTIALLY UNIFORMTHICKNESS WILL BE REMOVED FROM THE LOG AND DISCHARGED OUTWARDLY THROUGHSAID SLOTS WITH SAID SHAVING EDGES CUTTING SUBSTANTIALLY PARALLEL TO THEFIBERS IN SAID LOG AND SAID PARTING EDGES CUTTING ACROSS THE FIBERS ATAN ANGLE THERETO.